Electricity

Question 1

Polythene rod

Answer 1

Gains electrons

Question 2

Perspex rod

Answer 2

Loses electrons

Question 3

Earthing

Answer 3

Occurs when a charged object loses its charge to the earth through a conductor

Question 4

Static electricity

Answer 4

A build up of electric charge that can occur on good insulators e.g plastic

Question 5

AC

Answer 5

Alternating current changes very quickly, many times a second

Question 6

DC

Answer 6

Direct current goes in one direction only e.g. The current from a battery

Question 7

Mains supply

Answer 7

Is AC it flows at a potential difference of 230 Volts

Question 8

The ring circuit

Answer 8

Made of live, neutral and earth wires. Sockets are tapped off at points along this ring circuit

Question 9

Fuse

Answer 9

Is a safety device that prevents the circuit from overheating. It will not melt when it is too hot breaking the circuit

Question 10

Circuit breaker

Answer 10

Is used in the fuse board of the home, and this trips, to stop the flow of current from entering the house

Question 11

Live wire

Answer 11

Is brown and carries most electricity it is connected to the plugs fuse on the right hand side

Question 12

Neutral wire

Answer 12

Is blue and is connected to the left hand side

Question 13

Earth wire

Answer 13

Is a safety wire, no electricity flows in the earth wire unless the appliance it is attached to becomes “live” eg a toaster, in this case the earth wire would carry the current to the earth instead of you electrocuting yourself should you touch the toaster

Question 14

Heating effect

Answer 14

Boil water in a kettle, immersion heater, electric cooker, fuse in plug

Question 15

Chemical effect

Answer 15

Electroplating cheap metal with more expensive metal e.g. silver, electrolysis (splitting) of water, mobile phone battery

Question 16

Magnetic effect

Answer 16

Electromagnet made with a wire wrapped around a nail, electric motor, speakers, circuit breaker in fuse board

Question 17

Electronics

Answer 17

Is the careful and exact control of tiny amounts of electric current

Question 18

A Diode

Answer 18

Is a component that will allow current to flow in one direction only

Question 19

Forward biased

Answer 19

If the positive end of a battery is connected to the positive end of a diode the diode is said to be “Foward Biased” and current can flow

Question 20

Reverse Biased

Answer 20

If the positive end of the battery is connected to the negative end of the diode it is said to be “Reverse Biased” and no electricity can flow

Question 21

A diode can be used

Answer 21

To change alternating current into direct current

Question 22

Electronic devices such as radios, tape recorders and calculators

Answer 22

Need low voltage direct current

Question 23

Light emitting diode

Answer 23

Is a diode that gives out light when a current flows through it

Question 24

Current will only flow when LED is

Answer 24

Forward biased

Question 25

LED’s use only tiny currents so

Answer 25

A resistor must be connected in series with it

Question 26

LED’s are useful as they are

Answer 26

Cheap,nee liable and long lasting and use far less current than other light bulbs

Question 27

Light Dependent Resistor (LDR)

Answer 27

Is a resistor whose resistance depends on light

Question 28

When light falls on a LDR

Answer 28

It’s resistance decreases, this low resistance will allow a current through the circuit